1. Field of the Invention
This invention relates to a semiconductor integrated circuit device and more particularly to a semiconductor integrated circuit device having a fuse box and a register which holds information transferred from the fuse box, and an error detecting method for checking destruction of information held in the register.
2. Description of the Related Art
Electrical fuses (for example, current fusible type fuses) and optical fuses (for example, laser fusible type fuses) can each be used to program information of 0/1 according to cutoff/non-cutoff of an electrical path. That is, the fuse is a type of programmable ROM, and since information can be programmed according to physical destruction of cutoff/non-cutoff of the electrical path, the storage holding characteristic is semi-permanent. Due to the above advantage, recently, fuses have received much attention as means for programming information which is required to be semi-permanently programmed in the semiconductor integrated circuit device, thus are widely used. Information which is required to be semi-permanently programmed, is, for example, redundancy information of a semiconductor memory.
However, the fuse is accompanied by physical destruction when programming. Therefore, during the programming, an accident in which a semiconductor device in the semiconductor integrated circuit chip will be destroyed may occur in some cases. In a recent semiconductor integrated circuit device, the above problem is solved by collectively arranging fuses in a region called a fuse box and isolating them from an internal macro region in which the integration density of the semiconductor device is high.
However, the fuse box is provided in a portion separated from the internal macro region. Therefore, if access is made to the fuse box from the internal macro region, the operation speed will be extremely lowered. Therefore, a method for transferring information read out from the fuse box to a temporary storage circuit, for example, a register provided in the internal macro region and holding the information programmed in the fuses in the register is used.
As a prior art reference in which the technique for transferring information programmed in the fuses to the register is described, for example, U.S. Patent Publication No. 6,490,219 is given.